The 36-year-old said he
had “very real concerns and worry about this bid’s impact on
those close to me.”

Ummuna was considered by many to be a front-runner in the race to
succeed Ed Miliband, who resigned earlier this month after his
party suffered a crushing defeat in the UK general election.

The Shadow Business Secretary said in a statement: “As a
member of the Shadow Cabinet, I am used to a level of attention
which is part and parcel of the job. I witnessed the 2010
leadership election process close up and thought I would be
comfortable with what it involved.

“However since the night of our defeat last week I have been
subject to the added level of pressure that comes with being a
leadership candidate.

“I have not found it to be a comfortable experience.

“One can imagine what running for leader can be like,
understand its demands and the attention but nothing compares to
actually doing it and the impact on the rest of one's life.

“Consequently after further reflection I am withdrawing my
candidacy.”

He added that he thought he had understood “the scrutiny and
attention a leadership contest would bring.”

Umunna said he would continue to serve as Shadow Business
Secretary and hoped to “play a leading role” in Labour's
campaign to keep the UK in the EU during the impending in/out
referendum.

He also publicly apologized to all those who have supported him
in his bid.

Former Culture Secretary Ben Bradshaw told the BBC it was a
“terrible loss” because he was the candidate the
Conservatives “feared the most.”

“And if it's the result of pressure on an extended family or
an extended group of friends, I think that’s a very sad
reflection on our political culture,” he commented.

There are now four declared candidates in the race: Shadow Health
Secretary Andy Burnham; Shadow Home Secretary Yvette Cooper,
Shadow International Development Secretary Mary Creagh; and
Shadow Health Minister Liz Kendall.